Note: Descriptions are shown in the official language in which they were submitted.
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DETONATOR CONTROL SYSTEM
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to the use of one or more detonators
in a geophysical
exploration process to generate seismic information and more particularly is
concerned with
the provision of information, to an operator or to a control system, which
facilitates the
implementation of a seismic blasting system.
[0002] In a geophysical exploration process use can be made of one or more
electronic
detonators to create an explosion which generates seismic waves. Reflections
of the
seismic waves by geophysical formations and discontinuities in the earth are
measured and
are processed to obtain an indication of properties below the earth's surface.
[0003] In a seismic application boreholes are normally primed well in advance
before firing
the respective detonators in the boreholes. It is not uncommon for a period of
up to two or
three months to pass, once a detonator is loaded into a borehole, before the
detonator is
fired.
[0004] It is therefore essential to have continuity of information for an
unattended primed
borehole with a seismic blasting detonator may otherwise be inadvertently
initiated.
[0005] Generally adequate techniques are available in the prior art to prevent
a detonator
from being prematurely initiated by an extraneous signal. For example a
detonator may be
responsive only to a specific encoded firing signal.
However a substantial degree of time
and effort is required to "re-establish" a seismic system in a safe and
effective manner after a
dormant period of several weeks (say). Each borehole must be found and
identified.
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Information pertaining to each detonator in the borehole must be validated
and, only then,
can controlled firing of each detonator take place to generate the required
seismic
information.
[0006] Typically, when the time comes for firing the detonators, an operator
using a hand-
held blaster traverses a blast site and locates the individual boreholes. A
connection is
made to the respective detonator and, subsequently, after validation
processes, blasting
takes place. As a seismic site can be extensive in area and, given that a
fairly long period
may have passed from the time a blast site was established to the time at
which blasting is
to take place, care must be taken to ensure that the detonators are correctly
identified and
are correctly fired.
[0007] An object of the present invention is to provide a blasting system
which lends itself to
use particularly in a seismic arrangement, in which this aspect is, at least
to some extent,
facilitated.
SUMMARY OF THE INVENTION
[0008] The invention provides a blasting system which includes a plurality of
boreholes,
wherein each borehole is respectively loaded with at least one detonator and
with an
explosive material, and at least one mobile device, under the control of an
operator, which
presents information to the operator on the location and identity of at least
one of the
boreholes, only if the borehole is within a predetermined distance of the
operator.
[0009] Depending on the extent of the predetermined distance the mobile device
may
present information on the location and identity of each borehole which is
within said
predetermined distance.
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[0010] The mobile device may include a tagger or a hand held blaster, a
communication
unit, a processor and an output device which provides visual or audible
information or both,
to an operator. The invention is not limited in this respect.
[0011] For example, within a given radius from the position of the operator,
which position is
coincident with the location of the mobile device, the system may present
information on
each detonator or borehole within that radius. The information may relate to
any of the
following: positional information, identity information i.e. the identity of a
borehole and the
identity of a detonator, and directional information e.g. route information of
a path to be
travelled by an operator to reach a particular detonator or borehole. The
invention is not
limited in respect of the nature of the information.
[0012] The size of the radius, which determines the extent of the area on
which information
is presented to the operator, may be adjustable.
[0013] The information may be held in the mobile device or it may be
transferred to the
mobile device, as appropriate, from a database at a central controller. The
system may
include a controller which on an ongoing basis verifies the location of the
mobile device (i.e.
the position of the operator) relative to positional information previously
collected and stored
e.g. in the mobile device or in a database at a central location. If an
information match is not
recorded then the system may automatically take appropriate action e.g. it may
generate a
warning message to the operator, or the system can log the event to allow
remedial action to
be taken.
[0014] The invention also extends to a method of controlling operation of a
blasting system
which includes a plurality of boreholes, wherein each borehole is respectively
loaded with at
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least one detonator and with an explosive material, wherein the method
includes the steps of
recording the identity and location of each borehole or detonator in the
system and of
subsequently using a mobile device which presents information on such identity
or location
to an operator of the device but only in respect of each borehole or detonator
which is in the
blasting system and which is within a predetermined distance of the operator.
[0015] There are two important aspects to the invention. The mobile device may
collect
information from each detonator within the predetermined area and compare this
to
previously collected and stored information using geographical data in order
to correlate the
collected information with the stored information.
Secondly, again using geographical
(positional) data as a control parameter, the relevant stored information is
made available to
an operator who can then verify that this information is accurate by using the
mobile device
as appropriate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention is further described by way of example with reference to
the
accompanying drawings in which:
Figure 1 illustrates, somewhat schematically, a detonator system according to
the invention,
and
Figures 2 and 3 illustrate aspects of the working of the system.
DESCRIPTION OF PREFERRED EMBODIMENT
[0017] Figure 1 of the accompanying drawings schematically illustrates a
blasting system 10
which includes a number of boreholes 12A, 12B ... 12N at a blast site 13 and
which is used
to establish a seismic arrangement. Each borehole is drilled to a
predetermined depth and is
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loaded with a respective explosive material 14A, 14B ... 14N and with one or
more
detonators 16A, 16B 16N. Each detonator 16A... 16N is connected via a
respective wire or
conductor 18A ... 18N to a respective connector 20A ... 20N located on a
surface 22. The
connectors (20A ¨ 20N) may be coupled via the respective conductors (18A ¨
18N) to a
5 surface harness or a bus (not shown) or use can be made of wireless
connection techniques
to establish communication between each detonator (16A ¨ 16N) and a central
controller 30.
[0018] In order to control aspects of the operation of the blasting system use
is made of the
central controller 30 which is connected to a database 32. An operator 34, who
traverses
the blast site 13, carries at least one mobile device 40 which includes a
processor 41, a
tagger 42, a handheld blaster 44, and a display 46. The device 40 also
includes a
transmitter/receiver unit 47 which communicates, wirelessly, with the central
controller 30.
The device 40 has output terminals in the form of a connector 48 which can be
coupled
directly to any of the connectors 20 on the surface 22. Alternatively a
wireless link can be
established under controlled conditions between the mobile device 40 and any
selected
connector 20 (or detonator 16).
[0019] In a seismic exploration arrangement the boreholes 12 are drilled in a
predetermined
pattern over a surface which is to be seismically mapped. Positional data,
determined for
example from a GPS system (not shown), relating to the position of each
borehole. is stored
in the database 32. Subsequently each borehole 12 is loaded with its
respective explosive
material 14 and detonator 16. At this time, or shortly thereafter, data (as
may be required for
seismic purposes) on each borehole installation is collected via the tagger
42.
[0020] An insert drawing in Figure 1 illustrates an electronic module 50A
associated with a
respective detonator 16A. Other components of the detonator 16A are not
illustrated. The
module 50A includes a logic/processor unit 52A, a memory unit 54A in which is
stored, inter
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alia, an identity number (56A) for the detonator and information (57A)
relating to the position
of the detonator, a communication unit 58A, and a battery 60A for powering
electronic
components of the detonator. The module 50A could form a part of the detonator
16A, or of
the respective connector 20A.
[0021] Figure 2 illustrates the mobile device 40, which contains one or both
of the tagger 42
and the hand held blaster 44, and which is carried by the operator 34 as the
operator
traverses the blast site 13. The mobile device 40 includes or is linked to a
GPS module 70
which continuously and automatically provides positional information to the
operator 34. The
operator 34 uses the processor 41 to set the extent of an area 72 by defining
a radius 74
which extends from the position of the mobile device 40 and which encloses the
area 72.
The setting of the radius 74 depends on a variety of factors including the
density of the
boreholes 12 at the blast site 13 and on the nature of the terrain on which
the blast site is
located.
[0022] As the operator 34 moves the geographical position of the area 72, in
an absolute
sense, also moves. If boreholes 12X and 12Y fall inside the area 72 then, at
that time. the
respective identifiers 56X and 56Y of the boreholes 12X and 12Y are presented
to the
operator 34 on the display 46. This is achieved by using the unit 47 to
communicate with the
central controller 30 so that positional information, previously stored in the
database and
pertaining to each of the detonators 16 at the blast site can be presented on
a continuous
basis to the operator.
[0023] The operator is then free to approach the borehole 12X, or the borehole
12Y. as he
chooses. The operator can then carry out further operations pertaining to the
establishment
of the seismic arrangement.
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[0024] Information relating to or arising from detonators and boreholes
outside of the area
72 is rejected or not processed and so is not presented to the operator 34 for
processing.
[0025] Directional information may be given to the operator 34 to assist the
operator to the
site of a chosen borehole. The directional information may be given by spoken
commands
produced by the processor 41 acting on a loudspeaker 75 using information
generated by
the GPS module 70, or the directional information may be visually conveyed to
the operator
34 on the display 46 by indicating a direction 76 to a chosen borehole 12X
with the direction
being specified at least with reference to an angular deviation 78 from a
reference plane or
line 80. These aspects are exemplary only and non-limiting.
[0026] A flow chart in Figure 3 illustrates some operational steps. A borehole
12N (as is the
case with all of the other boreholes in the blasting system 10), is initially
identified by means
of a unique number given to the borehole 12N or by means of an identifier 56A
which is
given to a detonator 16N placed in the borehole 12N at the time the blasting
system 10 is
initially established. This identification information is held in the database
32.
[0027] The GPS module 70, which is linked to the mobile device 40 carried by
the operator
34, generates positional information 82 pertaining to the location, at the
time. of the GPS
module 70.
[0028] The operator 34 selects the borehole 12N by specifying the identity
number 57N of
the borehole 12N or the identifier 56N of the detonator 16N which is held in
the borehole
12N. The positional information 57N which is held in the database 32 and the
corresponding
detonator identity number 56N are then presented to the operator 34 on the
display 46 of the
mobile device 40. This borehole positional information 57N is compared to the
positional
information 82 (of the borehole 12N) which is being measured at the time by
the GPS 70
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which is linked to the mobile device 40. If the outcome of a comparative
process 90 is
positive then the setting up of the seismic arrangement can continue (step
92). If the
outcome of the comparative process is negative (step 94) then the operator 34
is warned of
the discrepancy e.g. the operator is possibly not at the correct borehole or
some other error
has occurred. The event is logged as may be required and, if necessary,
appropriate
remedial action is taken (step 96).
[0029] The control sequence substantially enhances the operation of a seismic
exploration
process in that the detonators (12A ... 12N) must be correctly identified
before firing takes
place. Additionally, the locating of the individual detonators 16 and
boreholes 12 by an
operator 34 is facilitated.
